The present invention relates to a semiconductor optical sensing apparatus including a semiconductor optical sensor chip.
The conventional semiconductor optical sensing apparatus includes a semiconductor optical sensor chip, such as a charge coupled device (CCD) and a metal oxide semiconductor (MOS) device, enclosed in a ceramic casing for practical use. The semiconductor optical sensor chip detects an image or images focused onto it through an aspherical glass lens.
FIG. 20(a) is a plan view of a conventional semiconductor optical sensing apparatus. FIG. 20(b) is a cross sectional view taken along line 20bxe2x80x9420b of FIG. 20(a). FIG. 21(a) is a plan view of another conventional semiconductor optical sensing apparatus. FIG. 21(b) is a cross sectional view taken along line 21bxe2x80x9421b of FIG. 21(a). FIG. 22(a) is a plan view of a further conventional semiconductor optical sensing apparatus. FIG. 22(b) is a cross sectional view taken along line 22bxe2x80x9422b of FIG. 22(a).
In these figures, the optical sensing apparatus includes a sensor chip, an aspherical glass lens combined with the sensor chip and a ceramic casing that houses the sensor chip and the aspherical glass lens. The sensor chip may be a CCD image sensor, an MOS image sensor, a photodiode, an ultraviolet ray sensor or other optical sensors.
Referring now to FIGS. 20(a) and 20(b), the semiconductor optical sensing apparatus includes a detecting section and an optical section. The detecting section includes a semiconductor optical sensor chip 111, a ceramic casing 112, lead frames 113, bonding wires 114 and a transparent plate 116. The sensor chip 111 is die-bonded to the casing 112. The lead frames 113 include lead pins. The bonding wires 114 connect the internal terminals of the sensor chip 111 and the lead frames 113. The transparent plate 116 is fixed to the open end of the casing 112 with a layer 115 of glass having a low melting point or of adhesive.
The sensor chip 111 is mounted on the inner bottom face of the casing 112 and sealed in the casing 112 by the transparent plate 116. The space enclosed by the casing 112 and the transparent plate 116 is filled with a transparent filler (not shown) or with gas. The detecting section is fixed to a printed circuit board 117 by soldering the lead frames 113 to the printed circuit board 117.
The optical section includes an aspherical glass lens 118, a lens fixing frame 120 and a pressing metal jig 121. The lens fixing frame 120 is fixed to the printed circuit board 117 with an adhesive 119 so that the aspherical glass lens 118 may focus an image or images onto the sensor chip 111. The pressing metal jig 121 fixes the aspherical glass lens 118 to the lens fixing frame 120.
The semiconductor optical sensing apparatus thus constructed detects an image or images focused by the aspherical glass lens 118 on the sensor chip 111 through the transparent plate 116, and outputs the detected image signals through the lead frames 113. The semiconductor optical sensing apparatus works as an image sensor.
Referring now to FIGS. 21(a) and 21(b), the semiconductor optical sensing apparatus includes an optical section, that is different from the optical section of the semiconductor optical sensing apparatus shown in FIGS. 20(a) and 20(b). In FIGS. 21(a) and 21(b), the optical section includes an aspherical glass lens 118, a lens fixing frame 124 and a pressing metal jig 125. The lens fixing frame 124 is fixed to the printed circuit board 117 by frame support columns 122 and screws 123 so that the aspherical glass lens 118 may focus an image or images onto the sensor chip 111. The pressing metal jig 125 fixes the aspherical glass lens 118 to the lens fixing frame 124.
Referring now to FIGS. 22(a) and 22(b), the semiconductor optical sensing apparatus includes an optical section different from the optical section of the semiconductor optical sensing apparatus shown in FIGS. 20(a) and 20(b). The semiconductor optical sensing apparatus of FIGS. 22(a) and 22(b) is different from the optical sensing apparatus of FIGS. 20(a) and 20(b) in that the detecting section and the optical section are integrated together in FIGS. 22(a) and 22(b).
In FIGS. 22(a) and 22(b), the optical section includes an aspherical glass lens 118, a lens fixing frame 126, an adhesive layer 127 and a pressing metal jig 128. The aspherical glass lens 118 is mounted on the lens fixing frame 126. The adhesive layer 127 bonds the lens fixing frame 126 to the transparent plate 116 of the detecting section. The pressing metal jig 128 fixes the aspherical glass lens 118 to the lens fixing frame 126. The aspherical glass lens 118 is positioned so that the aspherical glass lens 118 may focus an image or images onto the sensor chip.
When the space inside the casing 112 is filled with gas, the surface of the semiconductor optical sensor chip and the bonding wires 114 are deteriorated depending on the gas in the sealed casing 112. For avoiding the deterioration, it is necessary to fill the space inside the casing 112 with an inert gas. The filling of the space inside the casing 112 with the inert gas increases manufacturing steps. Even when the space inside the casing 112 is filled with the inert gas, it is necessary to control the temperature and humidity precisely so that the characteristics of the semiconductor optical sensing apparatus may not change. Moreover, the gas leakage test, that should be conducted after the space inside the casing 112 is filled with the inert gas, increases the manufacturing cost.
When the space inside the casing 112 is filled with a transparent filler (not shown) to protect the sensor chip 111 and to seal the casing 112, the transparent filler expands or contracts due to temperature variations around and inside the casing 112. The expansion and contraction of the filler cause parting between the casing 112 and the filler, bubbles in the filler, and in the worst case, breaking of the bonding wires 114. The expansion and contraction of the filler due to temperature variations change the distance between the upper surface of the transparent plate 116 and the surface of the sensor chip 111. The distance change further causes variation of the optical characteristics of the semiconductor optical sensing apparatus.
In the conventional CCD image pick-up apparatuses and the conventional MOS image pick-up apparatuses, a ceramic casing is combined with an aspherical glass lens to prevent the displacement of the focal point due to temperature variations. As shown in FIGS. 20(a) through 22(b), one or more aspherical glass lenses 118 are mounted on the lens fixing frame 120, 124 or 126 and fixed to the lens fixing frame 120, 124 or 126 by the pressing metal jig 121, 125 or 128. This structure increases the cost and labor for manufacturing the optical system.
When an insulative plastic casing and an aspherical plastic lens are employed to reduce the manufacturing costs of the optical system, the plastic casing also expands or contracts in response to expansion or contraction of the transparent filler. The expansion and contraction of the casing further cause larger displacement of the focal point, that is hazardous for obtaining a clear image.
In view of the foregoing, it is an object of the invention to obviate the above described problems of the conventional semiconductor optical sensing apparatuses.
It is another object of the invention to provide an economical semiconductor optical sensing apparatus having a simple structure, that is less affected by temperature variations.
It is a further object of the invention to provide a semiconductor optical sensing apparatus that facilitates preventing deterioration and variation of the optical characteristics, elongating the life of the apparatus and improving the reliability.
According to an aspect of the invention, there is provided a semiconductor optical sensing apparatus including: a casing having one or more openings in its bottom portion and being made of an electrically insulative material; wiring means extending from the inside to the outside of the casing; a semiconductor optical sensor chip bonded to the bottom portion of the casing and having a terminal disposed on its surface; connecting means connecting the terminal and the wiring means; a transparent filler filling a space inside the casing, the one or more openings absorbing a volume change of the transparent filler caused by its expansion or contraction; a transparent plate disposed above the semiconductor optical sensor chip with the transparent filler interposed in-between, the transparent plate being adhered or welded to the casing; and focusing means adhered or welded to the transparent plate in a positional relationship such that the focusing means focuses an image or images onto the semiconductor optical sensor chip. The focusing means, the transparent plate and the casing are made of the same material or materials having almost the same thermal expansion coefficients.
According to another aspect of the invention, there is provided a semiconductor optical sensing apparatus including: a casing including one or more openings in its bottom portion and being made of an electrically insulative material; wiring means extending from the inside to the outside of the casing; a semiconductor optical sensor chip bonded to the bottom portion of the casing and having a terminal disposed on its surface; connecting means connecting the terminal and the wiring means; a transparent filler filling a space inside the casing, the one or more openings absorbing a volume change of the transparent filler caused by its expansion or contraction; and focusing means positioned above the semiconductor optical sensor chip with the transparent filler interposed in-between such that the focusing means focuses an image or images onto the semiconductor optical sensor chip. The focusing means is adhered or welded to the casing. The focusing means and the casing are made of the same material or materials having almost the same thermal expansion coefficients.
According to a further aspect of the invention, there is provided a semiconductor optical sensing apparatus including: a casing having one or more openings in its bottom portion and supporting rods protruding inwardly, the casing being made of an electrically insulative material; wiring means extending from the inside to the outside of the casing; a semiconductor optical sensor chip bonded to the bottom portion of the casing and having a terminal disposed on its surface; connecting means connecting the terminal and the wiring means; a transparent filler filling the space inside the casing; a transparent plate positioned above the semiconductor optical sensor chip with the transparent filler interposed in-between to form one or more openings between the casing and the transparent plate, the transparent plate being adhered or welded to the supporting rods of the casing; and focusing means adhered or welded to the transparent plate in a positional relationship such that the focusing means focuses an image or images onto the semiconductor optical sensor chip. The one or more openings in the bottom portion of the casing and the one or more openings between the casing and the transparent plate absorb the volume change of the transparent filler caused by its expansion or contraction. Also, the focusing means, the transparent plate and the casing are made of the same material or materials having almost the same thermal expansion coefficients.
According to a still further aspect of the invention, there is provided a semiconductor optical sensing apparatus including: a casing including one or more openings in its bottom portion and supporting rods protruding inwardly, the casing being made of an electrically insulative material; wiring means extending from the inside to the outside of the casing; a semiconductor optical sensor chip bonded to the bottom portion of the casing and having a terminal disposed on its surface; connecting means connecting the terminal and the wiring means; a transparent filler filling the space inside the casing; and focusing means positioned above the semiconductor optical sensor chip with the transparent filler interposed in-between to form one or more openings between the casing and the focusing means such that the focusing means focuses an image or images onto the semiconductor optical sensor chip. The focusing means is adhered or welded to the supporting rods of the casing. The one or more openings in the bottom portion of the casing and the one or more openings between the casing and the transparent plate absorb the volume change of the transparent filler caused by its expansion or contraction. The focusing means and the casing are made of the same material or materials having almost the same thermal expansion coefficients.
According to a still further aspect of the invention, there is provided a semiconductor optical sensing apparatus including: a casing having one or more openings in its bottom portion and being made of an electrically insulative material; wiring means extending from the inside to the outside of the casing; a semiconductor optical sensor chip bonded to the bottom portion of the casing and having a terminal disposed on its surface; connecting means for connecting the terminal and the wiring means; a transparent filler filling the space inside the casing, the one or more openings absorbing the volume change of the transparent filler caused by its expansion or contraction; an iris plate, disposed above the semiconductor optical sensor chip with the transparent filler interposed in-between and adhered or welded to the casing, for limiting light beams entering the semiconductor optical sensor chip; and focusing means adhered or welded to the iris plate in a positional relationship such that the focusing means focuses an image or images onto the semiconductor optical sensor chip. The focusing means, the iris plate and the casing are made of the same material or materials having almost the same thermal expansion coefficients.
Advantageously, the focusing means includes at least a pair of lenses, and the iris plate has apertures corresponding to the lenses.
Preferably, the semiconductor optical sensing apparatus further includes covering means for covering the one or more openings.
The semiconductor optical sensing apparatus may further include coating means for coating the transparent filler in the one or more openings.
Also, the semiconductor optical sensing apparatus may further include protecting means for protecting the transparent filler.
Preferably, the transparent filler is transparent silicone gel.